A fuse protector is mainly used to protect wires or devices in a power distribution system. That is to say, when fault current occurs in the power distribution system, the fuse protector fuses rapidly to shut off the current so as to prevent the spread of the accident. Currently, the conventional structure of the fuse protector substantially consists of a fuse protector base made of insulating materials, a fuse carrier made of insulating materials, and standard fuses. The fuse protector base comprises fuse protector base contacts contacted with both ends of the fuses, and terminals electrically connected with the contacts. The main function of the fuse carrier is to support the fuses so that the fuses can be easily inserted into or pulled out of the fuse protector base, and can be replaced and maintained conveniently. The fuse protector can be applied in many situations, especially in photovoltaic power generation, since the fuse protector has the advantages of low price, convenient maintenance and so on. As the world pays attention to the environment and strongly supports the renewable energy, the photovoltaic power generation industry has developed rapidly, and thus needs the fuse protector that can satisfy higher requirements, especially on a high pressure, a small volume, high safety and reliability. Many manufacturers of the fuse protector pay attention to these aspects. By market research and comparison of the fuse protectors available from numerous manufacturers, the inventor found that the existing fuse protector in the market have the following drawbacks. First, the distribution box has a low utilization rate of space due to the arrangement of the fuse protectors. Second, it is difficult to mount a leakage module and a Hall module in a photovoltaic combiner box by the existing arrangement of the fuse protectors. And third, the fuse protector generally comprises two breaking points which are applied high pressure during insertion and pulling operation, and an arc may occur and ablate the contact points, thus leading to short lift and poor safety. The specific analysis is as follows.
(1) The distribution box has a low utilization rate of space due to the arrangement of the fuse protectors. The conventional photovoltaic power generation system gathers the electric energy produced by 16 groups of solar panels into a combiner box, and then inputs the electric energy into an inverter. The fuse protectors in the combiner box function to protect the solar panels, and the electric elements and wires in the combiner box, and also to isolate the power source. The current fuse protector applied to the photovoltaic power generation field generally comprises one incoming line terminal and one outgoing line terminal. Two fuse protectors for a positive electrode and a negative electrode so as to protect a circuit under 1000V. Meanwhile, in order to ensure safe electric clearance and creepage distance between the positive electrode and the negative electrode, the positive electrode and the negative electrode are arranged separately from each other in the photovoltaic combiner box, with a large enough safe distance. The current combiner box system with the fuse protector generally has 32 fuse protectors, which are divided into a group for positive electrode and a group for negative electrode, and each group has 16 fuse protectors. Each group is arranged in the combiner box in a modular form. In order to ensure the safe creepage distance and the electric clearance, the two groups are spaced at a certain distance vertically or horizontally. Obviously, the above-mentioned arrangement of the fuse protectors causes a waste of volume of the combiner box and amount of the wires. Meanwhile, the same problem also exists in an alternating current distribution system. Generally, the arrangement of alternating current fuse protectors comprises two forms: one form in which the fuse protectors are individual from each other and each fuse protector has one fuse and two terminals, one for incoming and the other one for outgoing, and the other form in which a plurality of individual fuse protectors are disposed side by side, with the fuse protector bases thereof connected together or formed into an integrity, wherein the fuse protectors have a plurality of terminals, and the fuses are inserted individually for convenient management. The above two forms are the same in volume, but also have a low utilization rate of the space in the power distribution box.
(2) In the photovoltaic combiner box system, in order to monitor the power generation of each branch, a leakage module and a Hall module are generally installed. The leakage module mainly serves to detect whether there is a leakage in each branch. The leakage module detects leakage current by inducing imbalance of the current in the positive and negative electrodes via mutual inductors, which all the positive and negative wires pass through. The Hall sensor mainly detects the current of each branch, and it monitors magnitude of the current based on Hall Effect. In fact, the leakage module and the Hall sensor are formed as a whole respectively. However, when applied to the combiner box system, the fuse protectors for the positive electrode and the fuse protectors for the negative electrode are arranged separately, and each group comprising 16 fuse protectors is arranged at an individual region in the combiner box. If it is necessary to install the leakage module and the Hall sensor, wires needs to be connected to the leakage module and the Hall sensor, thus wasting wires and occupying space.
(3) High pressure is applied to the breaking points during insertion and pulling operation of the fuse, resulting in short lifetime and poor safety of the fuse protector, particularly in the direct current system. The conventional fuse protector either has one fuse protector base cooperated with one fuse, or has a plurality of bases arranged horizontally cooperated with a plurality of independent fuses. Generally, the fuse may be inserted and pulled rotatably or directly. Pulling rotatably means removing one end of the fuse away from a stationary contact and then removing the other end of the fuse, that is, the two ends of the fuse are pulled out in a sequential order. Pulling directly means removing two ends of the fuse directly away from two stationary contacts at the same time. Pulling directly is better than pulling rotatably on the aspects of both the voltage on the breaking point and the breaking velocity. In the photovoltaic direct current system, the voltage is 1000V, and different from the alternate arc, the direct arc has no zero crossing point and is difficult to extinguish. The extinguishing of the direct arc mainly depends on breaking velocity, breaking distance, and number of the breaking points. That is to say, faster breaking velocity, longer breaking distance, and more the breaking points are helpful to the rapid extinguishing of the arc. Multiple breaking points can equally bear the breaking voltage, which is important to arc extinction. From the above analysis, it can be seen that the disadvantage of pulling rotatably is particularly significant. Rotatable separation is to separate one end of the fuse at first from the stationary contact and then separate the other end of the fuse from the stationary contact, and thus the operation speed is lower than that of pulling directly. Besides, there is only one breaking point, and the voltage applied to the breaking point is very high, thus it is difficult for the arc to be extinguished, particularly in high altitude area where the arc cools slowly due to the thin air. Since the photovoltaic power station project always chooses high altitude area due to plenty of sunshine thereof, it is necessary to solve the technical problem of preventing the arc from ablating the contact position. The ablation of the arc affects the electrical conductivity and lifetime of the fuse protector, or threatens the safety of the operator, which will bring serious consequences. For pulling directly, there are two breaking points equally bearing the breaking voltage. The fuse protector adopting the way of pulling directly has more advantages than the fuse protector adopting the way of pulling rotatably due to a higher operation speed. The combustion of the arc greatly affects the contact position even if there are two breaking points.